Wireless communication systems including electronic identification devices, such as radio frequency identification devices (RFIDs), are known in the art. Such devices are typically used for inventory tracking. As large numbers of objects are moved in inventory, product manufacturing, and merchandising operations, there is a continuous challenge to accurately monitor the location and flow of objects. Additionally, there is a continuing goal to determine the location of objects in an inexpensive and streamlined manner. One way of tracking objects is with an electronic identification system.
One presently available electronic identification system utilizes a magnetic coupling system. Typically, the devices are entirely passive (have no power supply), which results in a small and portable package. However, such identification systems are only capable of operation over a relatively short range, limited by the size of a magnetic field used to supply power to the devices and to communicate with the devices.
Another type of wireless communication system is an active wireless electronic identification system. Attention is directed towards commonly assigned U.S. Patent Application Ser. No. 08/705,043, filed Aug. 29, 1996, now U.S. Pat. No. 6,130,602, incorporated herein by reference, and which describes such active systems in detail.
These systems include integrated circuit devices which include an active transponder and are intended to be affixed to an object to be monitored. The devices are capable of receiving and processing instructions transmitted by an interrogator. A device receives the instruction, if within range, then processes the instruction and transmits a response, if appropriate. The interrogation signal and the responsive signal are typically radio-frequency (RF) signals produced by an RF transmitter circuit. Because active devices have their own power sources, such do not need to be in close proximity to an interrogator or reader to receive power via magnetic coupling. Therefore, active transponder devices tend to be more suitable for applications requiring tracking of a tagged device that may not be in close proximity to an interrogator. For example, active transponder devices tend to be more suitable for inventory control or tracking.
It is often desired to determine or otherwise obtain the range of communications of a wireless communication system. For example, electronic identification systems may be installed in different environments, such as a variety of warehouse configurations, manufacturing plants, retail premises, etc. The communication range of an electronic identification system, or other -wireless communication system, can be greatly impacted by the environment in which the system is utilized. Thus, it is often desired to determine the communication range of the system following implementation of the same in a particular environment and application.